Energy Budgets of Ectothennic Vertebrates

Ecological energetics provides a unifying focus for ecologicalstudies. Heat energy budget analysis is used to predict thebody temperatures of animals and their microclimatic requirements.Climate space diagrams, transient energybalance models and operativeenvironmental temperature models predict daily and seasonalactivity patterns, predator—prey interactions and energyrequirements of vertebrate ectotherms. Food energy budget (resourceallocation) models are used toinvestigate the life history processesof fish, amphibians and reptiles. Heat energy budgets and foodenergy budgets interact through their effects on body temperatureand metabolism. Coupled heat, food and mass balance equationscan serve as aunified energy budget model and are useful indetermining limits on the energy available to an animal forgrowth and reproduction. Bioenergetic models have been successfullyapplied to some reptiles and fish. Complete energy budgets arenow needed for other ectothermic vertebrates.     

Consider a Spherical Lizard: Animals, Models, and Approximations

Ecologists and physiologists have used biophysical models toanswer questions and investigate hypotheses about animal biologyfor over 20 years, but many investigators do not use such techniquesbecause such modelling is perceived as an arcane art. Indeed,there is no magic strategy to allow all ecologists to modelany biophysical problem accurately by means of simple recipes.In practice, biophysical ecology depends heavily on mathematicaland engineering principles. But, it need not be impenetrable.Here we discuss relatively simple models that can be incorporatedinto many ecological studies. We also discuss some of the importantapproximations and assumptions inherent in our treatments ofradiative, convective, evaporative, and conductive heat transfer.In so doing, we hope to encourage the use of such models, andto engender an appreciation of when and under what conditionspredictions from such models are most likely to be misleading.Thus, we hope to help ecologists to get into and, hopefully,out of trouble in biophysical ecology.